Preheat oven to 350 degrees F. Grease a 9x13 inch pan. In medium size bowl, stir together 1 cup sugar, 3 cups flour, baking powder, salt and cinnamon. Use a fork or pastry cutter to blend in the shortening and egg. Dough will be crumbly. Pat half of the dough into the prepared pan.In another bowl stir together the sugar and cornstarch. Gently mix in the blueberries. Sprinkle the blueberry mixture evenly over the crust. Crumble remaining dough over the berry layer. Bake in a preheated oven for 45 minutes, or until the top is slightly brown. Cool completely before cutting into squares.